Discard Elf during fight & Yuppie Water

[DRaider_GR]

Hi there. I'm new in Munchkin world with my group, we've played 4 games so far and we've loved it. I've spent some hours reading rulings about card combinations, but came across a situation i am not sure what happens.

I'm an Elf of level 9 and fighting a level 4 Leperchaun with +5 against Elves so we are tied with 9 and losing.
I play Yuppie Water which gives Elves +2 and a thief successfully backstabs me -2. (9-9, losing)
I play +3 Freezing Explosive Potion and another thief fails to backstab me, then plays +10 Humongous to monster. (12-19, losing)
I play +5 Magic Missile & -5 Baby to monster (17-14), they answer with +5 Intelligent monster. (17-19, losing)
I say I don't want to be an Elf anymore and so monster goes -5. (17?-14)
Last move, they play +2 Nasty-Tasting Sports Drink to monster. (17?-16)

And here comes my question. Normally if you have a Race/Class related item in Use, you turn it sideways when you discard your Race/Class, so you only Carry it. But what happens with Usable Once Items like Yuppie Water I used in fight above. Does the +2 still counts to my total or when i discard the Elf race i must not count it anymore?
The other players didn't notice that and because it was a late game I said nothing to win and finish it. But because we are new gamers I would like to know and inform them of what happens, next time.

[MunchkinMan]

If you're in combat, you don't turn an Item sideways, to indicate you are no longer using it, since that would be against the rules. After the combat, you will have to turn it sideways. However, you no longer get a bonus from it. The same would go for any one-shot Items in play. If a one-shot says it helps only an Elf or Elves, the Item is still in the combat, but it no longer provides a bonus to you if you went from being an Elf to not being one. On the flip side, since it was your turn, you could become an Elf again to get the bonus, but it was hardly worth it in this circumstance.

Also, there is no failing to backstab. The card doesn't offer any form of chance with respect to backstabbing. A Thief discards a card (from his hand or in play), he backstabs, giving a player in combat a -2 penalty, and that's all there is to it. That means you were at 10-19 when Humongous was added to the Monster.

So, in this case, when you cast off your Elf Race, your combat strength went from 15 to 13, and the Leperchaun went from 19 to 14. Thus, the final combat strength, based on how you described it, would have been 13-16, with you losing the combat. The Nasty-Tasting Sports Drink was superfluous, but not unwise, in case you had an ace up your sleeve (you didn't provide enough information about what your hand looked like to the other players).

[DRaider_GR]

You made it clear MunchkinMan and that's what i thought too, but wasn't sure. But yes, I did wrong about thief backstabing fail, so the fight had to be different. We forgot and thief rolled dice which is only for stealing. That's what happens when you play late after 3 hours. :D
Thank you.

[MunchkinMan]

You posted while I was editing. You should go back and read again, since you have a misunderstanding with respect to backstabbing that I missed in my first pass on the response.

[DRaider_GR]

Yeap, and i was editing while you were making the above post. But, ok, everything is clear, thank you.

[MunchkinMan]

Well, I'm glad we've quite crossing paths and that everything's clearer now. :-)